This invention relates to drill bits, specifically drill bit assemblies for use in oil, gas and geothermal drilling. Often drill bits are subjected to harsh conditions when drilling below the earth's surface. Replacing damaged drill bits in the field is often costly and time consuming since the entire downhole tool string must typically be removed from the borehole before the drill bit can be reached. Bit balling in soft formations and bit whirl in hard formations may reduce penetration rates and may result in damage to the drill bit.
U.S. Pat. No. 4,098,363 by Rhode et al., which is herein incorporated by reference for all that it contains, discloses a drill bit employing spaced shaped cutters in arrays separated by fluid channels in which there are positioned arrays of nozzles suitable for bit cleaning and detritus removal action.
U.S. Pat. No. 5,361,859 by Tibbitts, which is herein incorporated by reference for all that it contains, discloses a drill bit for use with earth drilling equipment, the drill bit having a body and movable cutting members variably positioned between a first position in which the diameter defined by the cutting members is generally equal to or less than the diameter of the drill bit body and a second position in which the diameter defined by the cutting members is greater than the diameter of the drill bit body.
U.S. Pat. No. 5,794,725 by Trujillo et al., which is herein incorporated by reference for all that it contains, discloses a drilling structure having a body defining at least one primary channel and at least one secondary channel therein to initiate and maintain recirculation of an amount of drilling fluid back through the secondary channel to maintain positive independent flow of drilling fluid through each primary channel of the drilling structure.
U.S. Pat. No. 6,253,864 by Hall, which is herein incorporated by reference for all that it contains, discloses a drill bit that combines the forces of high rotational torque and percussive impact with impact-resistant shear cutting inserts in order to increase formation penetration rates, particularly in deep wells were borehole pressure is high. The drill bit may also be used in cooperation with high-pressure nozzles that augment penetration, cool the shear cutting inserts, and remove the chips.